Cooling chamber temperature control well arrangement

ABSTRACT

IN A DRINKING WATER COOLING CHAMBER OF THE TYPE HAVING A SERIES OF REFRIGERANT COOLING COILS WRAPPED ABOUT THE COOLING CHAMBER, A TEMPERATURE CONTROL WELL ARRANGEMENT FOR RECEIVING A CAPILLARY TEMPERATURE SENSING ELEMENT IN WHICH THE WELL TAKES THE FORM OF A TUBE EXTENDING FOR SUBSTANTIALLY THE HEIGHT OF THE CHAMBER AND HAS ITS LOWER PORTION BONDED TO AT LEAST ONE OF THE COOLING COILS NEAR THE LOWER POSITION OF THE CHAMBER, AND AN UPPER PORTION OF THE WELL BEING BONDED DIRECTLY TO THE COOLING CHAMBER. A SUBSTANTIAL PORTION OF THE WELL TUBE BETWEEN THE BONDING LOCATIONS IS SPACED OUT OF CONTACT FROM THE COILS ALONG WHICH THE TUBE EXTENDS.

IFIG.3.

28 LJ-m INVENTOR I Eugene W. Scott BY ATTORNEY Feb. 9, 1971 E'L w. SCOTT COOLING CHAMBER TEMPERATURE CONTROL WELL ARRANGEMENT 'Fi'l ed=M arch 17, 1969 3,561,228 COOLING CHAMBER TEMPERATURE CONTROL WELL ARRANGEMENT Eugene W. Scott, Columbus, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 17, 1969, Ser. No. 807,713 Int. Cl. F2511 17/02 U.S. Cl. 62-201 8 Claims ABSTRACT OF THE DISCLOSURE In a drinking water cooling chamber of the type having a series of refrigerant cooling coils wrapped about the cooling chamber, a temperature control well arrangement for receiving a capillary temperature sensing element in which the well takes the form of a tube extending for substantially the height of the chamber and has its lower portion bonded to at least one of the cooling coils near the lower position of the chamber, and an upper portion of the well being bonded directly to the cooling chamber. A substantial portion of the well tube between the bonding locations is spaced out of contact from the coils along which the tube extends.

BACKGROUND OF THE INVENTION Field of the invention The invention relates generally to water cooling chambers for drinking water coolers, and relates more specifically to the structural arrangement for locating a temperature sensing element in the proper relation to the cooling chamber for exercising better temperature control.

Description of the prior art Two known ways of arranging a temperature sensing element for the cooling chamber of a drinking water cooler are to locate the sensing element inside the chamber so as to be substantially directly responsive to the temperature of the liquid being chilled and, alternatively, to attach a control well for the temperature sensing element directly to the refrigerant coils wrapped about the exterior of the cooling chamber. Each of these arrangements has its particular advantages and disadvantages.

As to the first arrangement, one disadvantage is that a control with a rather narrow differential is required, which in turn becomes expensive because calibration is critical. The immersed control is subject to reacting quickly to the temperature of unchilled water admitted into the chamber so that the control may then cause the refrigerating unit to restart before the refrigerant metering device allows for stabilization of the refrigerant circuit. The location of the control well in the cooling chamber may be difficult because of the potential loss of control arising from the inversion of cooled water which occurs at temperatures below about 39 F. Also the formation of ice on the walls of the chamber may occur before the control reacts to the chilling of the water since the ice insulates the water being chilled from the cold chamber wall.

Y The advantages of the direct connection of the control well to the refrigerant coils, in which the control responds "United States Patent into the cold chamber and hence sufficient time is allowed for the refrigerant circuit to stabilize before the control restarts the compressor. However, a disadvantage of the direct bonding to the refrigerant coils is that the rapid changes in refrigerant tube temperature during normal cycling may cause the refrigerant system to cycle more rapidly than is necessary. Also, the actual cooled water temperature for a given set of control operating temperatures is influenced by heat leak along the control well and the sensing element tubing.

The aim of my invention is to provide an improved control well arrangement for a cooling chamber which yields at least most of the advantages of the arrangements noted above, and avoids some of the disadvantages.

SUMMARY OF THE INVENTION In accordance with the invention the control well has a lower portion thereof bonded to at least one of the lower refrigerant coils on the chamber, and has its upper portion bonded directly to the chamber wall. Preferably the intermediate length of the control well is spaced apart from the refrigerant coils lying between the bonding locations. In one quite satisfactory arrangement I provide a U bend at the lower end of the control well so that the bight of the U serves as a stop for the end of the sensing element inserted into the tube and also facilitates having a fixed distance between the bonding locations at the lower end of the control well and the end of the sensing element.

DRAWING DESCRIPTION FIG. 1 is an exploded perspective view of a drinking water cooler of one type having a cooling chamber to which my invention is applicable;

FIG. 2 is an elevational view of a cooling chamber having refrigerant coils wrapped thereabout and with the control well applied in accordance with the invention; and

FIG. 3 is a top view of the arrangement of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The totality of the water cooler illustrated in FIG. 1 is described in some detail in Ter Bush and Scott, US. patent application No. 790,003. The parts of particular concern in connection with this invention are the cooling chamber and temperature control arrangement which generally occupy the front right and front center portions of the arrangement as shown in FIG. 1.

The cooling chamber assembly generally designated 10 includes an inner metallic, upright cylinder 12 having a bottom inlet from supply pipe 14 and a top outlet 16, the cylindrical cooling chamber having refrigerant cooling coils 18 wrapped tightly about the circumference of the chamber for the purpose of extracting heat from the chamber when refrigerant is pumped through the coils. Substantially the entirety of the cooling chamber is thermally insulated from ambient by the insulating wrapper 20 on the exterior of the cooling chamber assembly.

The temperature controller is conventional in the sense that it comprises a switch and bellows portion 22, the bellows being in communication with a fluid charged capillary tube 24, the portion of which is disposed to be influenced by the cooling chamber temperature being termed the temperature sensing element. The temperature controller operates in conventional fashion in that sufficient movement of the bellows in a direction corresponding to expansion of the fluid reflecting an increase in the cooling chamber temperature will cause the switch of the assembly 22 to energize the refrigerant compressor and, conversely, contraction of the fluid reflecting a decreased temperature of the cooling chamber will result in opening of the switch of the assembly 22 to shut down the compressor and refrigerant system operation.

Referring now to FIGS. 2 and 3, which show the cooling chamber and refrigerant coils before the termal insulation 20 is applied, it is noted that details of one satisfactory interior construction are disclosed in US. patent application No. 657,126, now US. Pat. 3,475,922 and considerations of the particular arrangements of spacing of the refrigerant coils 18 are described in the US. patent application Ser. No. 657,127, now US. Pat. 3,479,839. However it is not considered that the invention is limited to either of these two particular constructions.

A control well 26 is provided and connected to the cooling chamber assembly to receive a temperature sensing element which reflects the temperature of the chamber and its contained water for effecting control of the operation of the cooler. The well 26 takes the form of an openended metallic tube which in the illustrated embodiment has a U bend portion 28 at its lower end and a right angle turn portion 30 at its upper end. The upper bend need not be a right angle and is only necessary to have the control well touch the chamber and pass through the insulation at a convenient location. The lower portion of the well is bonded at the locations 32, 34 and 36 to the three lower turns of refrigerant coil 18 to place the well in good heat transfer relation with these turns. Thus the bonding may simply be a solder connection. The upper bend portion 30 is bonded by a highly heat conductive connection 38 directly to the Wall of the chamber 12.

Both ends of the well 26 may. for cost reasons, he left open. The temperature sensing element 40 in the form of the capillary tube is inserted in the upper portion 30 of the well and pushed into the well tubing until its lower end is stopped by the turn formed by the bight of the U-shaped portion 28 at the bottom of the chamber. Thus the location of the bottom end of the capillary or temperature sensing element 40 is easily fixed by abutting the bight portion of the bottom end 28. It is important to fix the location of the end of the capillary tube with respect to the attachment of the well to the refrigerant tube because the temperature of the surface of the liquid refrigerant in the control capillary controls the operation of the control and the temperature of this surface is influenced by the distance of this surface from the point of contact of the well with the refrigerant tubing. It will be appreciated that other stop locations could be devised by providing a kink or some other irregular shape in the well configuratron.

It will be especially apparent from observation of FIG. 3 that the intermediate portion of the well 26 is spaced outwardly away from the outer circumference of the refrigerant coils enough to insure that in the final assembly the intermediate portion does not contact the refrigerant coils, but does not stick out so much as to take up an inordinate amount of space. For manufacturing purposes the spacing indicated as the gap 42 in FIG. 3 may be established as about to inch.

Some observations as to the general theory of operation of this type of temperature control arrangement may aid in appreciating some of the features of the invention. With the charged bellows and capillary tube arrangement, the coldest point of the capillary tube will tend to provide the control. Both the control well 26 and the capillary 40 are of a good heat conducting material (such as copper) and accordingly there is heat conduction from the ambient space about the insulated cooling chamber assembly through the capillary 40, and also to a degree through the well 26 to the extent that it is influenced by the ambient temperature about the cooling chamber assembly. In an operating situation the higher the ambient temperature about the cooling chamber, the greater the period of operation of the refrigerant system, all other things being equal. This accordingly tends to further increase the ambient temperature about the cooling chamber. The tendency caused by the higher ambient temperatures is an increase of the temperature of the control capillary at the point of the liquid level inside this tube. The tendency toward this increased temperature must be offset by a lowering of the temperature of the refrigerant tubing required to cut-off the control because the control is designed to cut-off at a fixed temperature at all times. Thus without the control well being bonded to the water chamber the above effect is aggravated.

In contrast therewith, in accordance with my arrangement the bonding for heat transfer between the well and the chamber itself results in a stabilization of the control well temperature to a substantially greater degree than with the prior art, irrespective of ambient temperature variations about the cooling chamber assembly. This occurs when the chamber temperature is maintained as desired which is more or less constant temperature regardless of ambient temperature. Thus the heat leak along the control well in the area of the above liquid level is essentially constant for normal variations of the ambient temperature. Hence, the reduced refrigerant temperature in the chamber coils is not necessary to balance the higher temperature in this part of the well when the well is not in thermal contact with the chamber at the upper end. With the well temperature stabilized by thermal contact to the water chamber, the refrigerant temperature in the chamber coils can be more constant for varying ambient temperatures and hence the water temperature (e.g. 50 F.) inside the chamber will be more uniform.

Observations from testing the water temperature at the control cutoff in degrees Fahrenheit with ambients varying between 70 and about the cooling chamber indicate that the actual water temperatures at the control cutoff will vary from as high as 535 F. to as low as 385 F. at the extremes of the ambient temperature when the control well is not attached to the chamber itself. However when the control well is so connected or bonded, the water temperature at the control cutoff ranged at the extremes of ambient between 49.8 F. and 45 F. The improvement is accordingly apparent.

What is claimed is:

1. In a drinking water cooler having an insulated water cooling chamber about which refrigerant cooling coils are tightly wrapped for the extraction of heat from said chamber when said coils receive refrigerant, a temperature control arrangement comprising:

a temperature control well in the form of a tubular member extending along the outer side of said coils for a substantial portion of the length of said chamber;

means bonding the lower end portion of said well to at least one of the lower ones of said coils to place said lower end portion of said well in direct heat transfer relation with said coils, said lower end portion of said well being out of direct heat transfer relation with said chamber;

means bonding an upper portion of said well directly to said chamber to place said upper portion of said well in direct heat transfer relation with said chamber, with said upper portion of said well being out of direct heat transfer relation with said coils; and

a temperature sensing element disposed in said well.

2. In an arrangement according to claim 1:

the major portion of the length of said well between the lower portion and the upper bonding location is spaced away from said coils to provide a lag in heat transfer between said coils and said major portion of said well.

3. In an arrangement according to claim 1:

said well includes means formed in the lower portion thereof providing a stop for the free end of said temperature sensing element.

4. In an arrangement according to claim 3:

said stop means includes said lower portion of said well formed into a generally retroverted shape in which the retroversion forms said stop, and the end portion of said well spaced from said stop provides said lower portion bond locations. 5. A fluid cooling chamber and temperature control sensing arrangement in which:

said chamber comprises a fluid storage space of metallic construction;

refrigerant cooling coils of metallic construction wrapped in spiral configuration on the outside of and for a substantial portion of the length of said chamber;

a tubular control well of metallic construction extending for a substantial portion of the length of said chamber, generally transversely to, and on the outside side of, said refrigerant coils, said well including one end portion thereof bonded directly to at least is generally at one end of said chamber, and said bonding location of said well to said chamber is generally at the other end of said chamber.

7. An arrangement according to claim 6 wherein:

said bonding location of said well to said chamber is adjacent the end of said well through which said sensing element is inserted.

8. An arrangement according to claim 6 wherein:

the major portion of the length of said control well between said bond locations is spaced apart from the remainder of said refrigerant coils.

References Cited UNITED STATES PATENTS one of said refrigerant coils and being out of direct 15 2,278,226 3/1942 Tijlylol' 62 394 contact with said chamber, and another portion of 2359790 10/1944 Rmehart 62 395 said well being bonded directly to the wall in good 2,481,662 9/1949 Hastmgs 62-394 heat transfer relation of said chamber and out of 2,912,142 11/1959 Schultz direct contact with said coils; and

a temperature sensing element inserted in said well for a distance at least equal to a major portion of the length of said well.

6. An arrangement according to claim 5 wherein:

said bonding location of said well to said cooling coils 20 MEYER PERLIN, Primary Examiner US. Cl. X.R. 

